The objectives of the proposal are to define the pathways and factors controlling long chain fatty acid oxidation. Carnitine palmitoyltransferase A and B are being purified to study kinetics and determine if they are isoenzymes. Antibodies will be produced to aid in the evaluation. Specific inhibitors are being used to characterize the transferase activities. Acyl-d-carnitines are being used to characterize carnitine palmitoyltransferase B whereas 2-tetradecylglycidic acid is being used for transferase A. The transferase activities in skeletal muscle offer a contrast with liver enzymes because of the differences in kinetic parameters. We are working on the identification and quantitation of acylcarnitines by high pressure liquid chromatography. Normal phase chromatography using ion-pairing is being developed as the Method of Choice. Acylcarnitines will be quantitated by ion-pairs; partition coefficients and resolution factors will be assessed. The initial step of B-oxidation, acyl-CoA dehydrogenase will be evaluated as the rate limiting step of B-oxidation at the mitochondrial capacity for long chain fatty acid oxidation.